Power semiconductor devices integrated with clamp diodes having separated gate metal pads to avoid breakdown voltage degradation

1. A semiconductor power device comprising: a source region of a first conductivity type; a body region of a second conductivity type encompassing said source region; a first drain region of said first conductivity type disposed outside of edge termination; a gate separated by an insulating layer from channel region of said body region; a source metal layer connected to said source regions and said body regions; a first gate metal connected to said gate; a first drain metal connected to said first drain region; said source region, said body region, said gate and said first drain region formed in a top side of semiconductor chip; a gate-drain clamp diode connected between a second gate metal on the gate-drain clamp diode and said first drain metal, composed of multiple back-to-back polysilicon Zener diodes disposed outside of edge termination area without having said polysilicon Zener diode or said second gate metal cross over said edge termination; a second drain region formed on a bottom side of said semiconductor chip; a second drain metal layer connected to said second drain region; and said first and second gate metals connected together at a gate lead frame through at least one bonding wire.

2. The semiconductor power device of claim 1 is a trench IGBT wherein: said gate is a trenched gate; said source region is an emitter region of said first conductivity type; said body region is a base region of said second conductivity type; said first drain region is a first collector region of said first conductivity type; said source metal is a emitter metal; said first drain metal is a first collector metal; and said gate-drain clamp diode is a gate-collector clamp diode.

3. The semiconductor power device of claim 2 further comprises an on-resistance reduction implantation region having same conductivity type as said emitter region surrounding trench bottom of each said trenched gate.

4. The semiconductor power device of claim 2 is a PT trench IGBT further comprising: a heavily doped substrate of said second conductivity type; a first epitaxial layer of said first conductivity type grown on said substrate; a second epitaxial layer of said first conductivity type grown on said first epitaxial layer, having less doping concentration than said first epitaxial layer; and a second collector region of said second conductivity type is disposed on said bottom side of said substrate.

5. The semiconductor power device of claim 2 is a NPT trench IGBT further comprising: a lightly doped substrate of said first conductivity type; and a second collector region of said second conductivity type is disposed on the bottom side of said lightly doped substrate.

6. The semiconductor power device of claim 2 is a NPT trench IGBT further comprising: a lightly doped substrate of said first conductivity type; and a second collector region comprising alternately heavily doped regions with said first and second type conductivity formed on the bottom side of said lightly doped substrate.